The ultimate aim of research in this laboratory is the elucidation of the mechanism of oncogenesis by the avian tumor virus, avian myeloblastosis virus (AMV). The immediate objectives of this proposal are: 1. The isolation, purification and characterization of the DNA intermediate (Provirus) synthesized early in the replication of the virus. 2. The analysis of provirus fragments generated by restriction enzymes. 3. The study of provirus DNA synthesis and of the mechanism by which the provirus is integrated into cellular DNA. 4. The characterization of the integration site.